Note 21 - Unaudited Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2020		Sep. 30, 2020		Jun. 30, 2020		Mar. 31, 2020		Dec. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unaudited Quarterly Results Of Operations [Abstract]
Interest income	$ 10,859		$ 10,763		$ 10,740		$ 11,331		$ 11,600		$ 11,817		$ 11,712		$ 11,289		$ 43,693	$ 46,418	$ 43,200
Interest expense	1,338		1,433		1,506		2,168		2,435		2,635		2,601		2,453		6,445	10,124	8,185
Net interest income	9,521		9,330		9,234		9,163		9,165		9,182		9,111		8,836		37,248	36,294	35,015
Provision for loan losses	250		250		250		500		375		550		150		225		1,250	1,300	1,130
Non-interest income	3,547		2,809		2,817		(1,571)		2,210		2,144		1,654		2,309		7,602	8,317	4,892
Non-interest expense	7,611		7,197		6,869		7,278		7,632		6,955		6,793		6,724		28,955	28,104	25,885
Income before income taxes	5,207		4,692		4,932		(186)		3,368		3,821		3,822		4,196		14,645	15,207	12,892
Provision for income taxes	1,056		914		998		(406)		623		731		679		817		2,562	2,850	1,557
Net income	$ 4,151		$ 3,778		$ 3,934		$ 220		$ 2,745		$ 3,090		$ 3,143		$ 3,379		$ 12,083	$ 12,357	$ 11,335
Earnings Per Share - basic	$ 1.17	[1]	$ 1.07	[1]	$ 1.11	[1]	$ 0.06	[1]	$ 0.78	[1]	$ 0.88	[1]	$ 0.90	[1]	$ 0.97	[1]	$ 3.42	$ 3.53	$ 3.27
Earnings Per Share - diluted	$ 1.17	[1]	$ 1.07	[1]	$ 1.11	[1]	$ 0.06	[1]	$ 0.78	[1]	$ 0.88	[1]	$ 0.90	[1]	$ 0.97	[1]	$ 3.42	$ 3.53	$ 3.25

[1] Due to rounding, quarterly earnings per share may not sum to annual earnings per share